To cite earthtide in publications use:

Kennel J, Parker B (2025). earthtide: Parallel Implementation of 'ETERNA 3.40' for Prediction and Analysis of Earth Tides. doi:10.5281/zenodo.2673048, R package version 0.1.7, https://github.com/jkennel/earthtide.

Corresponding BibTeX entry:

  @Manual{,
    title = {{earthtide}: Parallel Implementation of 'ETERNA 3.40' for
      Prediction and Analysis of Earth Tides},
    author = {Jonathan Kennel and Beth Parker},
    year = {2025},
    note = {R package version 0.1.7},
    doi = {10.5281/zenodo.2673048},
    url = {https://github.com/jkennel/earthtide},
  }